I wanted to get this information out as requested by our members to let everyone know this is becoming an issue for many members, please read and understand the laws regarding shipping packages and using the USPS. Turning ANY priority packaging inside out to ship anything BUT priority mail is Illegal, buyers often get stuck paying the additional fees just to receive their packages. If you need polymailers, they can be bought for very cheap on both amazon and ebay as well as through some of our wonderful ds mama's. If you have any questions, feel free to pm a mod or admin for further clarification. From the USPS Site

Using Express Mail service or Priority Mail service envelopes for other mailIf any Express Mail service or Priority Mail service packaging or packaging supplies e.g., Priority Mail tape to seal a Parcel Post package, are used on any other class of mail, the applicable Express Mail or Priority Mail price will be charged.

Misuse may be a violation of federal law.

Turning the packaging inside out to conceal the Priority Mail / Express Mail insignia is specific misuse that is not allowed.

Any matter mailed in these free boxes is charged the appropriate Express Mail or Priority Mail price, regardless of how the packaging is reconfigured (including being turned inside out, cut, shrunk, enlarged, etc.) or how the markings are obliterated.
Mail dropped in a Collection Box receptacle using inappropriate packaging (including, for example, mailing Priority Mail items in an Express Mail box) is either:

Sent on as insufficient postage mail
OR

Returned to the sender

Treatment of this mail is based on the specific case as decided by the Post Office facility handling the mailpiece.NOTE: The USPS provides some packaging and supplies free of charge for: